This invention relates in general to the manufacture of electronic modules and more particularly to a method for controlling the loop height for wires used to interconnect specific circuit elements contained in such modules.
During the manufacture of certain electronic modules an apparatus called a wire bonder is used to provide an electrical connection between circuit elements using a plurality of wires. In certain RF modules the plurality of wires is used to provide a specific amount of inductance, and the height of such wires above a given reference plane within the module must therefore be controlled to a relatively close tolerance. Ordinarily this tolerance is selected based on the variation in one or more electrical performance specifications which occurs as a result of the variation in the height of these wires above the reference plane.
During manufacture the actual height of the connecting wires is ordinarily allowed to vary within this tolerance based on the electrical specification, and adjustments to the wire bond apparatus are made only when the wire height is outside tolerance based on the electrical specifications for the module.
Depending on the sampling rate used and the particular wire bond apparatus being used, the wire loop height may in a given case not only vary significantly from a desired nominal wire loop height, but in fact exceed the tolerance based on electrical specifications for a certain number of individual modules prior to detection by measurement of a given sample.